Josh Berkus wrote:
> Hackers,
>
> What purpose is served, exactly, by max_wal_senders?
>
> In order for a standby to connect, it must have a superuser login, and
> replication connections must be enabled in pg_hba.conf. How is having
> one more setting in one more file you have to enable on the master
> benefitting anyone?
>
> Under what bizarre set of circumstances would anyone have runaway
> connections from replicas to the master?
>
> Proposed that we simply remove this setting in 9.1. The real maximum
> wal senders should be whatever max_connections is.
I disagree - limiting the maximum number of replication connections is
important for my usecases.
Replication connections are significantly more heavilyweight than a
normal connection and right now I for example simply use this setting to
prevent stupid mistakes (especially in virtualized^cloudstyle environments).
What we really should look into is using a less privileged role - or
dedicated replication role - and use the existing per role connection
limit feature. That feature is unlimited by default, people can change
it like for every role and we can git rid of that guc.
Stefan